The way visualization pipelines are displayed has been considerably
reworked. A new class, VisualizationPipelineWrapper, is now responsible
for creating all necessary representations (VisualizationPipelineWidget,
PipelineMdiSubwindow) of a visualization pipeline and seamlessly
switching between them in response to the user's actions (window
dragging, key presses, etc). As a result, it's now possible to drag
visualization pipeline widgets out of the MDI area and turn them into
top-level floating windows.